Posted
by
timothy
on Monday August 15, 2011 @05:04AM
from the none-more-black dept.

thebchuckster writes "The darkest alien world ever spotted by astronomers has been discovered in the outskirts of our galaxy. 'It's darker than the blackest lump of coal, than dark acrylic paint you might paint with. It's bizarre how this huge planet became so absorbent of all the light that hits it,' David Kipping, an astronomer at the Harvard-Smithsonian Center for Astrophysics."

1) The #xxxxxx system describes what colour an object displays under specific conditions (for example, lighting), not an object's innate light reflection ability (albedo).2) The #xxxxxx system doesn't describe colour on an absolute scale; it only orders colours in an arbitrary space with an arbitrary metric. For example, there's no guarantee that #000002 is twice as bright as #000001, and there's no guarantee that #000000 is absolute black. Even whe

Giedi Prime is an industrial wasteland with a low photosynthetic potential, the planet's bio-resources depleted and its environment fouled with industrial pollution.[4] Rich in mineral resources, the economy of the planet is based on mining, refineries, and industrial manufacture. In Dune, Baron Vladimir Harkonnen and his heirs live in the "family city of Harko."[4]

Due to its ravaged environment, Giedi Prime has to import almost all of its requirement of organic products.

The original question I asked, "Where is Arrakis"; the bold answers that. And the word "Arrakis" is neither in my spell checker nor my dictionary, and I haven't read Dune in years, and I don't have the books with me now. It's not like Arrakis us real, even though its star is (and according to Wikipedia I doubt if it were there that it would be the least bit habitable).

Would it be possibly to build a Dyson Sphere around a single star in a binary system?Really, I'd like to know:) Am thinking it would be an order of magnitude harder (gravitational shear being 1 possible impediment), but could be? Then covering it is something to absorb sunlight from the other star could make sense....

I'd guess that the largest problem would be tidal forces, although with a strong enough, or flexible enough, material, this could be overcome. Otherwise, if the stars were far enough apart, and the Dyson Sphere small enough, it would be possible to minimise the tidal forces from the external star.

Would it be possibly to build a Dyson Sphere around a single star in a binary system?

Anything is possible with enough unobtanium, artificial gravity (unless you spin it up to ludicrous speed to make gravity - see Ringworld) and matter transmutation (if you believe the words of thousand-year-old ship's prostitutes).

Seriously, come back and ask that question when we know how to build a Dyson sphere around a single sun.

Anyway, I thought the original "Dyson sphere" concept was actually a cloud of satellites dense enough to capture all of the solar energy, rather than the rigid sci-fi version

You are correct, although I don't think there is any real stipulation that said densely packed cloud of satellites can't be attached to one another and therefore become a solid mass.

Orbital requirements. You'll need some satellites orbiting over the poles. If the satellites are attached to each other, the only satellites that are truly 'orbiting' are around the equator. The rest are moving too slow, and would fall into the sun without enough structural support to hold them aloft. Hence, unobtanium.

I'm sure there is a major flaw in the following hypothesis, but couldn't there be a "dyson sphere" around a planet for different reasons? Dyson Spheres are built around a star as a hypothetical optimal method of complete solar harvesting.

What if a species not quite that advanced built such a shell around their own world? One flaw is how to best simulate their sun for grass/animals. Holes in the sphere? A series of lights, or a few on a track, that go around the world as needed? It would work best if the species were nocturnal (either by natural or "artificial" evolution at this point). Considering this is "Jupiter sized" then this thing would have enough room for twenty-two Earths to go from one end to another at the equator. There could be a whole planet and moon system inside.

That much surface area and they might be able to easily simulate their sun on planet for wildlife and then some. According to Wikipedia Jupiter's surface area: 6.1419×1010 km2. Cut that in half since even if the sphere doesn't rotate half of it will be facing their sun, and you have the maximum usable space for solar cells or whatever they are using instead. How much energy would that produce? Unless this thing is a relic left behind, they might not need a full blown Dyson Sphere yet.

According to the article it is in that star's habital zone. So it is in the right spot if it were a converted habital world. Dyson Sphere may not be the correct term, but the concept itself completely off from what could be here.

Then again, it could be the universe's largest naturally formed piece of coal or we discovered the home hub of the all consuming nanite swarm.

Maybe that is the problem that they were trying to solve: their sun may have evolved to produce more visible light than what they needed, but they still needed the thermal energy. So they paint the sphere black to absorb the heat but not the visible light.

I'm sure there is a major flaw in the following hypothesis, but couldn't there be a "dyson sphere" around a planet for different reasons?

That's ridiculous! Anyone who knows anything knows that it is a massive computing devices connected to itself across quantum realities and powering itself from the entropy that exists at the end of the universe which it uses to generate random numbers for a interstellar casino.

There is a flaw in the Dyson Sphere concept too it's that to create a (solar) Dyson Sphere it would require more matter than in a given solar system. Which means (amusing you can't create matter from energy extremely efficiently) would need to transport matter from another solar system to complete it likely needing to destroy at least one other star in the process. So unless a Society has settled and depleted every solar system in the galaxy it's more efficient to move part of your society to another solar

For that matter, as long as we're doing solar system scale engineering, split the difference between making Dyson spheres and planets and make lots of orbitals [wikipedia.org], which are mini Dyson rings. They can achieve the living area of a planet and simulate the gravity of one with a tiny fraction of the material. As for the sun, forget about collecting its energy, just kill it. Once we've stopped the wasteful runaway fusion going on inside the sun, we can mine it for hydrogen to power our fusion reactors and only prod

There is a flaw in the Dyson Sphere concept too it's that to create a (solar) Dyson Sphere it would require more matter than in a given solar system.

Why would you need much matter? A cloud of solar panels, orbiting the Sun well within the orbit of Mercury (which would be providing the mass source for the satellites) would do the job.

At a sphere one million km in radius centered on the Sun (which as I understand is cool enough that some materials can stay solid indefinitely), Mercury would provide roughly 26 metric tons of mass per square meter of the sphere. Needless to say, you don't need that much mass per square meter and you have plenty of room e

There's a simpler and more paranoid explanation available. This is an alien home planet, and it's actually emitting huge amounts of various types of light. Our astronomical instruments, however, have been hacked to not show any of that- we're not supposed to know about alien civilizations, as it would stunt our development. Somealien didn't think this through and simply removed all the light from our data on that planet, resulting in an anomalously dark appearance. It's a software bug. Perhaps it'll be

What they could've done (and any advanced enough civilization is capable of this) is let their lives be simulated. First they started hooking up to the machines for fun and vacation, then they started getting addicted, then everybody got on it and this required more and more energy to simulate the world and to take the input of the connected individuals. Eventually the energy requirements required first a partial, then the war came for the resources that were left in the sunlight. Then they built a full Dys

Well, given how close this thing is to it's parent star, perhaps as a defense mechanism?

Think of an ordinary roughly Earth-sized planet within the habitable zone of a main sequence yellow star much like our own Sun. Now imagine a large gravitational mass (such as a black hole or rogue Gas Giant) passes close enough to perturb the orbit of the planet, causing it to slow down and fall inwards towards it's sun.

If the inhabitants of such a planet were more advanced than us, but not yet advanced enough to have

I admitted it wouldn't be a perfectly logical thing. The point I was trying to give is they wouldn't be utilizing energy from their world, but this would be a glorified solar panel. It would be a method of collector solar energy hitting their general solar system real estate.

The problem with that being that a Dyson sphere needs to be completely light absorbent on the *inside*, the outside really doesn't matter, although in this case it being light absorbent on the outside would also capture an insignificant amount of light from the primary.

Always assuming it's a binary system with one star being encapsulated.

In an SF context, that even makes some modicum of sense, in that you'd still have an actual sun and all...

Maybe it's from 2001 "All the monoliths are black, extremely flat, non-reflective rectangular solids."I remember Arthur C. Clarke's description of the blackness quite well, I'm thinking it was written slightly better than the summaries description of black.Unfortunately I don't have the book with me.

There was a manga years ago called 2001 Nights. It was a Sci-Fi anthology with a Kubrick/Clark 2001 influence.

In one of the stories a "10th Planet" is discovered in our solar system given the name Lucifer. It orbits our sun in a retrograde orbit (it goes the opposite direction of the other planets) and takes 666 years to complete an orbit. It's also the largest gas giant surpassing Jupiter. A mission to study the planet is launched and a number of tragic accidents befall the crew.

Maybe it's surface is made of polished platinum.. I jest, but I swear that stuff messes with my eyes; on one hand, it's shiny, but on the other, it's dark, almost black, and seems to just suck up light.

Please someone correct me if I'm wrong but I was under the impression that we've never seen any of the light reflected by a planet outside of our solar system. I thought the only methods of planet detection we currently have were to see the light it blocks from its host star, or to see the pull it has on its host star.

Surely they mean "orbiting"? "Circling" even? But "circumventing"?
I was about to make the same point, but the OED gives several meaning for "circumvent", one of which is "To go round, make the circuit of." Still, it is not the way that most people use the word; I think we can conclude that TFA is not written by one of the web's better science journalists.

It could just be a quirky, excessively tightly specified, phrasing during the 'dumb it down for the journalists' phase; but their might actually be a more astronomy-related reason:

If Kipping has had to get his hands dirty with any of the apparatus-side aspects of doing very precise optical telescope work, he may well have encountered substantially blacker-than-ordinary surface coatings being used to scrub unwanted light-scatter in sensitive optical gear. In the spirit of accuracy, he might have been emph

Returning no light is a tall order: If you are an efficient absorber of light, you'll heat up, and emit black-body radiation.(Assuming you don't just happen to occlude your star from the perspective of an earth observer during part of your orbit and get picked up that way, where being darker actually makes detection easier...)

There are probably some chunks of fairly dark and very cold material floating virtually undetectable in the void, but if you've got a nearby star irradiating you, it's just a matter